Thanks BrickR and Chas.
Chas -- I completely agree about the abrupt ending. It was the best I could do to tie everything together in under a minute. In the first three segments, I always made a transition to the next person by using a b-roll clip as a segment end/lead-in, but I even had to sacrifice one of those b-roll clips in the end of the last segment to keep the video to a minute. I've recognized this flaw since I first made the video!
As for audio, I have very, very limited experience with it. I don't know anything about proper mixing techniques or recording settings. This video's audio was recorded straight into the camcorder with a boomed Rode NTG-2 mic, and some background noise cleaned up in Soundtrack Pro. The furthest I go with mixing is making sure audio clip transitions are smooth through the use of crossfades, and keeping audio levels consistent. I know you're a professional audio mixer, so any advice is appreciated!